Disputation: Christian Zimmermann

The University of Oslo is closed. The PhD defence and trial lecture will therefore be fully digital and streamed directly using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation.

Ex auditorio questions: the chair of the defence will invite the audience to ask ex auditorio questions either written or oral. This can be requested by clicking 'Participants -> Raise hand'

Trial lecture

“The thermoelectric effect in semiconductors and its use in materials characterization and device applications”

 

Defects in Titanium Dioxide and Gallium Sesquioxide

Semiconducting materials are instrumental for the transition to a carbon-free society. Materials, such as titanium dioxide (TiO₂) or gallium sesquioxide (Ga₂O₃) are promising for a number of applications in energy harvesting and conversion. TiO₂ can be used to produce hydrogen from sun light and waste water, whereas Ga₂O₃ promises more efficient devices for electricity conversion. All semiconductors contain small amounts of microscopic imperfections (defects) which have a pronounced influence on the properties of the material. For example, defects influence what color of light a material absorbs or how well it will conduct electrical current. Often, it is challenging to identify the specific defects being present in a material. In this PhD project, a variety of experimental techniques were used to reveal the origins of specific defects being present in TiO₂ and Ga₂O₃. Some of the identified defects are shown to be highly relevant for applications of the materials. Moreover, it is demonstrated how the formation of certain defects which are detrimental for applications can be promoted or suppressed.

For further information

please contact Line Trosterud Resvold